The Core will provide electron and light microscopy imaging that is essential to accomplishing the goals of the individual projects. The intraceltular localization of proteins, nucleo-cytoplasmic transport of transcription factors, and imaging of myosin filaments are key to testing the hypotheses of this Program, and will require extensive use of confocal microscopy and electron microscopy. The core will provide training for individual investigators, align and calibrate these instruments, assist with preparation of specimens, and oversee scheduling of experiments and maintenance. The core includes a panel of local microscopy experts, who will conduct training and implement the latest upgrades and innovations. The Core staff wilt ensure that the Program gets effective and efficient use of these resources. A common core for microscopy brings with it other benefits in terms of sharing of protocols and reagents, trading of information on experiments in progress and nurturing a sense of camaraderie between individuals working on different projects, as they use common facilities and methodology to study related issues.